Using GRASS to fix topology

Started trying to use GRASS to solve some of the more difficult problems that I can't fix in PostGIS. Here's one of them. I've imported a shapefile of country borders and am trying to fix the topology. The screenshot shows a country border with a bunch of "x" marks that I *think* represent centroids. I'd like to take them out, and just have one, long, continuous line at the country border. Not sure how to do that yet.